Here's a couple pics of one of my sporter Mosin I did last year. Everyone is telling the truth when they say prep work matters. If you take your time, go slow and think about what you're doing it's actually really easy to do.

I roughed up all surfaces with 150 grit sandpaper before painting. As long as you paint in layers and let them dry completely before starting another you're good to go. I used the tan as a base layer and used a piece of poster paper as a stencil for the brown. This is the first time I ever spray painted anything and I don't think I did too bad! I used krylon flat camo paint and did about a million layers of clear coat after the paint dried. Good luck if you decide to paint one of yours.